RB30-252 Sex and Age as Factors in Cattle Feeding

Varying economic conditions and changes in the demands of the meat consuming public have been responsible for the turns that have taken place in the beef industry during recent years. Both feeder and producer must recognize and conform to these changes if they are to continue in business. Among the most important of these changes have been the turn toward the marketing of lighter cattle and the gradual disappearance from feed lots of two- and three-year-old animals. Furthermore, the cattle population of the United States is fast reaching stabilization with the resulting effect that more heifers are being marketed, since only one-fourth of the heifer crop is needed to replace worn-out breeding animals. Realizing the increasing importance of the heifer problem from the standpoint of the producer, feeder, and consumer, the Nebraska Experiment Station undertook to compare steers and heifers in a series of trials both in the feedlot and in the beef. It was hoped that these experiments would yield results which would bring out existing differences, if any, between steers and heifers both in quality and quantity of beef produced and thus provide or disprove many of the complaints against heifers. The results of these trials are summarized in this bulletin. Age as well as the sex factor has been considered, since two-year-olds, yearlings, and calves were included in these trials.

Environmental and Farm Management Factors Associated with Tuberculosis on Cattle Farms in Northeastern Michigan

Objective—To identify major environmental and farm management factors associated with the occurrence of tuberculosis (TB) on cattle farms in northeastern Michigan. Design—Case-control study. Sample Population—17 cattle farms with infected cattle and 51 control farms. Procedure—Each case farm (laboratory confirmed diagnosis of Mycobacterium bovis infection) was matched with 2 to 4 control farms (negative whole-herd test results within previous 12 months) on the basis of type of farm (dairy or beef) and location. Cattle farm data were collected from in-person interviews and mailed questionnaires. Wildlife TB data were gathered through state wildlife surveillance. Environmental data were gathered from a satellite image-based geographic information system. Multivariable conditional logistic regression for matched analysis was performed. Results—Major factors associated with increased farm risk of TB were higher TB prevalence among wild deer and cattle farms in the area, herd size, and ponds or creeks in cattle housing areas. Factors associated with reduced farm risk of TB were greater amounts of natural open lands in the surrounding area and reducing deer access to cattle housing areas by housing cattle in barns, barnyards, or feedlots and use of electrified wire or barbed wire for livestock fencing. Conclusions and Clinical Relevance—Results suggest that certain environmental and management factors may be associated with risk of TB on cattle farms.

RB31-258 The Contribution fo Nebraska Farm Women to Family Income Through Poultry and Dairy Products

This investigation was made in 1929-1930 for the purpose of studying the activities of Nebraska farm women in the raising of poultry and in the care of dairy products, to discover whether or not such activities resulted in a contribution to the family income. With this in view, a group of women were asked to keep records for one year (from April 1, 1929 to March 31, 1930) of the value and amount of dairy and poultry products sold or used, of all expense incurred in production, and of the time spent both by the homemaker herself and by all other members of the household, in the production and sale of dairy and poultry products. When this study was outlined it was intended to cover only actual cash addition to the family income. This, however, did not prove to be feasible, as a considerable portion of the contribution to the family income was in the form of dairy and poultry products used at home.

Risk of Disease from Wildlife Reservoirs: Badgers, Cattle, and Bovine Tuberculosis

Livestock face complex foraging options associated with optimizing nutrient intake while being able to avoid areas posing risk of parasites or disease. Areas of tall nutrient-rich swards around fecal deposits may be attractive for grazing, but might incur fitness costs from parasites. We use the example of dairy cattle and the risks of tuberculosis transmission posed to them by pastures contaminated with badger excreta to examine this trade-off. A risk may be posed either by aerosolized inhalation through investigation or by ingestion via grazing contaminated swards. We quantified the levels of investigation and grazing of 150 dairy cows at badger latrines (accumulations of feces and urine) and crossing points (urination-only sites). Grazing behavior was compared between strip-grazed and rotation-grazed fields. Strip grazing had fields subdivided for grazing periods of <24 h, whereas rotational grazing involved access to whole fields for 1 to 7 d each. A higher proportion of the herd investigated badger latrines than crossing points or controls. Cattle initially avoided swards around badger latrines but not around crossing points. Avoidance periods were shorter in strip- compared with rotation-grazing systems. In rotation-grazing management, latrines were avoided for longer times, but there were more investigative contacts than with strip-grazing management. If investigation is a major route of tuberculosis transmission, the risk to cattle is greatest in extensive rotation-grazing systems. However, if ingestion of fresh urine is the primary method of transmission, strip-grazing management may pose a greater threat. Farming systems affect the level and type of contact between livestock and wildlife excreta and thus the risks of disease.

Bovine Tuberculosis in Michigan Wildlife and Livestock

Since 1994, the state of Michigan has recognized a problem with bovine tuberculosis (TB), caused by Mycobacterium bovis, in wild white-tailed deer from a 12-county area in northeastern Lower Michigan. A total of 65,000 free-ranging deer have been tested, and 340 have been found to be positive for M. bovis. The disease has been found in other wildlife species, and, in 1998, in domestic cattle, where to date 13 beef cattle and 2 dairy cattle herds have been diagnosed with bovine TB. Unfortunately, the situation is unique in that there have never been reports of self-sustaining bovine TB in a wild, free-ranging cervid population in North America. Scientists, biologists, epidemiologists, and veterinarians who have studied this situation have concluded that the most logical theory is that high deer densities and the focal concentration caused by baiting (the practice of hunting deer over feed) and feeding are the factors most likely responsible for the establishment of self-sustaining TB in free-ranging Michigan deer. Baiting and feeding have been banned since 1998 in counties where the disease has been found. In addition, the deer herd has been reduced by 50% in the endemic area with the use of unlimited antlerless permits. The measures of apparent TB prevalence have been decreased by half since 1997, providing hopeful preliminary evidence that eradication strategies are succeeding.

Interaction Between Roughages and Corn Milling Byproducts in Finishing Cattle Diets

During ethanol production, starch is the primary nutrient fermented and the remaining byproducts are excellent sources of fiber and protein. In addition, inclusion of byproducts in finishing diets may reduce the incidence of acidosis. As a result, roughage level and quality could potentially be reduced in finishing diets containing byproducts. Three experiments were conducted to examine the effects of roughage and wet corn gluten feed (WCGF) in finishing cattle diets containing corn distillers grains plus solubles. Cattle fed finishing diets containing wet distillers grains plus solubles (WDGS) with no roughage had decreased DMI and ADG compared to cattle fed roughage. Within roughage level, ADG was similar for cattle fed alfalfa hay, corn silage or corn stalks when included on an equal NDF basis. Apparent total tract digestibility of OM, NDF, and CP linearly decreased and ruminal pH variables increased linearly due to increasing roughage levels. Roughage sources can be exchanged on an equal NDF basis in beef finishing diets containing 30% WDGS (DM basis). In finishing diets containing modified distillers grains plus solubles (MDGS), DMI linearly increased due to increasing roughage levels but ADG responded quadratically and was lowest for cattle fed diets without roughage. There was also a quadratic response for DMI and ADG due to WCGF inclusion level. Gain:feed decreased linearly with increasing roughage and WCGF inclusion levels. Feeding 15% WCGF resulted in similar cattle performance and carcass traits to cattle fed no WCGF in diets containing 30% MDGS, but cattle fed diets with 60% total byproduct inclusion made up of 30% WCGF and 30% MDGS had reduced performance (DM basis). Additionally, reducing corn silage inclusion level to 7.5% resulted in similar finishing cattle performance and carcass traits to cattle fed 15% corn silage in diets containing 30% MDGS with or without inclusion of WCGF. Elimination of roughage in diets containing either WDGS or MDGS resulted in negative impacts on finishing cattle performance, ruminal metabolism, and carcass traits.

Historical Observations of Humpback And Blue Whales in the North Atlantic Ocean: Clues to Migratory Routes and Possibly Additional Feeding Grounds

The seasonal distributions of humpback and blue whales (Megaptera novaeangliae and Balaenoptera musculus, respectively) in the North Atlantic Ocean are not fully understood. Although humpbacks have been studied intensively in nearshore or coastal feeding and breeding areas, their migratory movements between these areas have been largely inferred. Blue whales have only been studied intensively along the north shore of the Gulf of St. Lawrence, and their seasonal occurrence and movements elsewhere in the North Atlantic are poorly known. We investigated the historical seasonal distributions of these two species using sighting and catch data extracted from American 18th and 19th century whaling logbooks. These data suggest that humpback whales migrated seasonally from low-latitude calving/ breeding grounds over a protracted period, and that some of them traveled far offshore rather than following coastal routes. Also, at least some humpbacks apparently fed early in the summer west of the Mid-Atlantic Ridge, well south of their known present-day feeding grounds. In assessing the present status of the North Atlantic humpback population, it will be important to determine whether such offshore feeding does in fact occur. Blue whales were present across the southern half of the North Atlantic during the autumn and winter months, and farther north in spring and summer, but we had too few data points to support inferences about these whales’ migratory timing and routes.

Predator and Heterospecific Stimuli Alter Behavior in Cattle

Wild and domestic ungulates modify their behavior in the presence of olfactory and visual cues of predators but investigations have not exposed a domestic species to a series of cues representing various predators and other ungulate herbivores.We used wolf (Canis lupus), mountain lion (Puma concolor), and mule deer (Odocoileus hemionus) stimuli (olfactory and visual), and a control (no stimuli) to experimentally test for differences in behavior of cattle (Bos taurus) raised in Arizona. We measured (1) vigilance, (2) foraging rates, (3) giving up density (GUD) of high quality foods and (4) time spent in high quality forage locations in response to location of stimuli treatments. In general, we found a consistent pattern in that wolf and deer treatments caused disparate results in all 4 response variables. Wolf stimuli significantly increased cattle vigilance and decreased cattle foraging rates; conversely, deer stimuli significantly increased cattle foraging rate and increased cattle use of high quality forage areas containing stimuli. Mountain lion stimuli did not significantly impact any of the 4 response variables. Our findings suggest that domestic herbivores react to predatory stimuli, can differentiate between stimuli representing two predatory species, and suggest that cattle may reduce antipredatory behaviour when near heterospecifics.

Wildlife-Cattle Interactions in Northern Michigan: Implications for the Transmission of Bovine Tuberculosis

Bovine tuberculosis (Mycobacterium bovis) was discovered in northern Michigan white-tailed deer (Odocoileus virginianus) in 1994, and has been known to exist in Michigan cattle herds since 1998. Despite efforts to eradicate the disease in cattle, infection and re-infection of farms continues to occur, suggesting transmission among cattle, deer, or other wildlife reservoirs. The goals of this study were to document wildlife activity on farms and evaluate the possible role wildlife play in the ecology of bovine tuberculosis (TB) in Michigan. Visual observations were conducted on farms in a 5-county area of northern Michigan to document direct wildlife-cattle interactions (i.e., <5 m between individuals) and indirect interactions (e.g., wildlife visitations to food stores and areas accessible to cattle). Observations were conducted primarily during evening and early morning hours between January and August, 2002, and on a 24-hour schedule between January and August, 2003. Total observation time accumulated through the duration of the study was 1,780 hours. Results indicated that direct interaction between deer and cattle was a rare event; no direct interactions were observed during the first year, and only one direct interaction was observed during the second year. However, through the duration of the study 21 direct interactions were documented between cattle and turkey, and 11 direct interactions were documented between cattle and mammals other than deer. In total, 273 indirect interactions by deer, 112 indirect interactions by turkeys, and 248 indirect interactions by mammals other than deer were observed during the 2 field seasons combined. These data supported the hypothesis that indirect interactions among wildlife and cattle are a potential mechanism for the transmission of TB in Michigan. If direct interactions were important mechanisms of TB transmission to cattle in northern Michigan, my data suggested that feral cats were the species of most concern, even though there were more observations between turkey and cattle. Unlike cats, which can become infected with and transmit TB, there is no evidence for such pathogenesis in turkey.

Echinococcus Infections in Man and Animals in Kenya

1. Hydatid cysts are found in more than 30 per cent of all cattle, sheep and goats in Kenya, but the disease is prevalent in man only in the semi-desert area of Turkana. Up to the time of the present investigation the life-cycle of the parasite in East Africa had not been studied, but it was suggested that wild carnivores, such as hyenas and jackals, might be the main hosts of the adult worms. 2. One hundred and forty-three carnivores, representing 23 species, have been examined. Echinococcus adults were found in 27 out of 43 domestic dogs (Canis familiaris), in three out of four hunting dogs (Lycaon pictus), in one out of nine jackals (Thos mesomelas), and in three out of 19 hyaenas (Crocuta crocuta). 3. A detailed morphological study was made of the Kenya material. After comparison with specimens from other parts of the world, it was concluded that the only species occurring in Kenya was E. granulosus, but it is possible that the minor morphological and biological differences are evidence of distinct strains. Further laboratory studies are necessary to compare the parasite from man and animals in different parts of Kenya with material from elsewhere. 4. A search was made for larval hydatids in 92 ungulates representing 18 species, and in a miscellaneous collection of nearly 2,000 rodents and primates representing a further 31 species. Only one animal was positive, a wildebeest (Gorgon taurinus). 5. The infections in the wild carnivores were all very light; only domestic dogs were heavily infected. It is concluded that the main cycle of transmission in Kenya is between dogs and domestic livestock. 6. Turkana tribesmen are the most heavily infected people in Kenya, either because the strain of parasite is more pathogenic to man in that area, or, more probably, because of the intimate contact between children and the large number of infected dogs. A particularly dangerous custom in the area is the use of dogs to clean the face and anal regions of babies when they vomit or have diarrhea. No satisfactory explanation can be given for the rarity of the disease in man in many of the other areas of Kenya where hydatids are very common in domestic animals. 7. The control of the disease will depend upon an active health-education campaign, together with the destruction of all unregistered dogs and improvement in meat hygiene.